Ti掺杂赤铁矿纳米棒中表面偏析介导的太阳能水分解效率增强
Enhancement of the Solar Water Splitting Efficiency Mediated by Surface Segregation in Ti-doped Hematite Nanorods
AI总结：
本文通过对比氮气与空气退火的Ti掺杂赤铁矿光阳极，发现氮气退火引发Ti表面偏析形成伪板钛矿团簇，使光电流提升超200%，并提出一种简便廉价的表面工程方法以增强光电极化学活性。
摘要：
能带工程被广泛应用于面向太阳能水分解应用且技术上可扩展的光阳极。复杂且昂贵的制备方法往往是必需的，但通常只能获得平均性能。在此，我们报道了简单的光阳极生长和热退火方法，并实现了有效的能带工程结果。通过比较在氮气中退火与在空气中退火的Ti掺杂赤铁矿光阳极，我们发现前者光电流显著增强，增幅超过200%。利用电化学阻抗谱和同步辐射X射线光谱显微技术，我们证明氧化表面态和载流子密度增加是光电极化学活性增强的原因。研究发现表面态与Ti表面偏析形成的伪板钛矿团簇有关。光谱叠层衍射成像技术首次在Ti L3吸收边用于分离伪板钛矿团簇贡献所对应的Ti化学配位。结合电子显微镜研究和密度泛函理论（DFT）计算，同步辐射光谱显微数据明确证明了N2退火Ti掺杂赤铁矿纳米棒具有更优光电极化学活性的起源。最后，我们在此提出了一种简便且廉价的表面工程方法，超越了已知的氧空位掺杂，使基于赤铁矿的光阳极在光电极化学活性方面获得净增益。
英文摘要：
Band engineering is employed thoroughly and targets technologically scalable photoanodes for solar water splitting applications. Complex and costly recipes are necessary, often for average performances. Here we report simple photoanode growth and thermal annealing, with effective band engineering results. By comparing Ti-doped hematite photoanodes annealed under Nitrogen to photoanodes annealed in air, we found strongly enhanced photocurrent, of more than 200 % in the first case. Using electrochemical impedance spectroscopy and synchrotron X-rays spectromicroscopies we demonstrate that oxidized surface states and increased density of charge carriers are responsible for the enhanced photoelectrochemical activity. Surface states are found to be related to the formation of pseudo-brookite clusters by surface Ti segregation. Spectro-ptychography is used for the first time at Ti L3 absorption edge to isolate Ti chemical coordination arising from pseudo-brookite clusters contribution. Correlated with electron microscopy investigation and Density Functional Theory (DFT) calculations, the synchrotron spectromicroscopy data prove unambiguously the origin of the better photoelectrochemical activity of N2- annealed Ti-doped hematite nanorods. Finally, we present here a handy and cheap surface engineering method, beyond the known oxygen vacancy doping, allowing a net gain in the photoelectrochemical activity for the hematite-based photoanodes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
